Smooth the data and find major peaks

18 次查看（过去 30 天）
Megha
Megha 2018-12-19
评论： Luna 2018-12-26
I have attached a data which shows some periodic peaks.
Upon close observation, it can be found that the data is not continously increasing
or decreasing over a period of sinusodal curve. The data breaks after every several interval.
Can anybody help me smootheing the data and find major increasing and decreasing peaks?
I used several functions like
x2 = smooth(x1);
x2 = smoothdata(x1,'gaussian',20);
x2 = smooth(x1,'loess');
There are still errors and I cannot observe peaks.
Can anyone please help.
  1 个评论
Adam
Adam 2018-12-19
If you have the SIgnal Processing Toolbox then
doc findpeaks
can help find the peaks.
I don't know what you mean by 'there are still errors' though. There are numerous ways to smooth data, it depends on the data and what is noise and what is true data that should be retained. I have sometimes used Savitzky–Golay filters for this, but gaussian smoothing or even mean smoothing can work depending how aggressive you need the smoothing to be.

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Luna
Luna 2018-12-20
编辑：Luna 2018-12-20
findpeaks is built-in function of Matlab and it already works for detecting peaks and locations. Try below:
load('matlab.mat');
y1 = GGG1_qzss;
x1 = (1:numel(y1))'; % creates a time series for 1 seconds each you can use different time samples also
figure;
plot(x1,y1,'r');
hold on;
MPH = 8; % minimum peak height you can change it if you want
MINW = 100; % minimum peak width
[pks,locs] = findpeaks(y1,x1,'MinPeakHeight',MPH,'MinPeakWidth',MINW);
% pks: peak values
% locs: location of peaks in array
plot(x1(locs),pks,'bo');
  3 个评论
显示 1更早的评论
Megha
Megha 2018-12-26
@ Luna,
Thank you it worked for me.

请先登录，再进行评论。

更多回答（1 个）

Sarah Crimi
Sarah Crimi 2018-12-19
编辑：madhan ravi 2018-12-19
There is an open source function called peakdet.m. Using this function, you have to set the delta which determines what is a peak. For instance when I used this,
delta1=0.000005;
[max_m, min_m]=peakdet(m, delta1);
The link the open source file is below:
https://www.mathworks.com/matlabcentral/fileexchange/47264-peakdet

类别

在 Help Center 和 File Exchange 中查找有关 Smoothing and Denoising 的更多信息

标签

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by